andyr wrote:So why would you use tubes in a phono stage at all, if some tube (hybrid!) phono stages use JFETs for the first (extremely low input) gain stage, to reduce noise?
If you ever get to hear a Rhea or similar at home, Andy, you'll know why. If you already have then you should know already. It's not always about noise for some listeners and in any case, as LD points out, the surface noise of even quiet vinyl is usually way above the noise floor of any good phono stage, solid-state or tube. As I alluded to earlier, I've heard Rheas contribute to some high-volume playback and I've not noticed noise as a distraction. Looking at other parameters, tubes have some compelling features, even in a phono amplifier. The overload margin is often gigantic relative to semiconductor designs and I duly noted, in the Stereophile review of the Rhea, that John Atkinson measured the highest overload margin he ever had to that date. Add to that the definitive characteristic of tubes that many listeners prefer - their tendency to sound better when the signal is using the non-linear portion of the envelope, another way of saying that the distortion is more euphonic.
On the subject of hybrid circuits generally, Audio Research released a couple of seminal products 25 years ago (SP10 & M300) in which a conscious effort was made to combine the two component types in a way that would simultaneously use the virtues and cancel the artefacts of each type, especially in the SP10 preamplifier. Both products were hugely successful (I owned two pairs of M300s). By the gist of EveAnna Manley's justification for using the JFET in the Steelhead it would appear that Manley were thinking the same way as ARC.